Ambulatory insulin infusion systems may be used for the therapy of Diabetes Mellitus. Ambulatory insulin infusion systems may include an insulin pump designed to be carried by a Person with Diabetes (hereinafter PwD) substantially continuously night and day. Ambulatory insulin infusion systems may to administer insulin into the PwD's subcutaneous tissue via a subcutaneous cannula, which can be replaced by the PwD every few days. Insulin pumps commonly administer insulin according to a basal administration profile which is typically pre-programmed and varies over the time of day. In addition, insulin pumps can be designed to administer larger insulin boli on demand, e.g., to compensate for the intake of food comprising carbohydrates and to lower undesirably raised blood glucose values. An insulin pump is disclosed, for example, in WO 2003053498 A2 to which reference is made for a typical design and typical features of such devices.
Discreetness of an ambulatory infusion system is a factor for the acceptance of continuous subcutaneous insulin infusion by many PwDs who may want to draw minimal attention, if any, towards their disease. Therefore, insulin pumps are designed to be carried in a concealed manner, e.g. in a trousers pocket, in a holster at a belt or as adhesive patch which is directly attached to the skin. The achievable discreetness for operating and programming the devices, however, may be limited. The devices are often coupled to a subcutaneous cannula via infusion tubing and carried at locations where they are not easily accessible. A meal bolus may be programmed prior to a meal, which may involve measuring a blood glucose value in a public environment. Therefore, meal bolus programming may impact the discreetness of an ambulatory infusion system.
A typical procedure for programming a bolus is described in the following for a commercially available system. The system allows comparatively discreet operation because it includes, in addition to an insulin pump, a separate diabetes manager with an integrated blood glucose measurement module that allows control over most functions of the pump wirelessly via a radio frequency (hereinafter RF) interface. The diabetes manager has a similar physical appearance (i.e., size and look) to a cell phone. Insulin pumps are generally substantially smaller in size and accordingly only provides a limited user interface, i.e., the diabetes manager provides a larger and more comfortable user interface. It can accordingly be operated in a comparatively discrete and convenient way.
When a PwD intends to take a meal, the following steps (A)-(D) are typically performed:
(A) Taking a blood glucose measurement. This includes the sub-steps of (i) removing a test strip from a container; (ii) placing the test strip in a corresponding socket of the diabetes manager, thus switching the device on; (iii) piercing the skin with a lancet or piercing device; (iv) placing a drop of blood on a corresponding section of the test strip; (v) reading the measured blood glucose value from a display; and (vi) removing and disposing the used test strip.
(B) Marking the measured blood glucose value. For this purpose, the diabetes manager may offer a list of situations such as, for example, “before meal”, “after meal”, “before sports,” and the like. An item from the situations may be selected via keys. While this step is optional, it adds information for diary keeping and evaluation purposes. The information may also be considered in the subsequent step of determining the insulin bolus amount.
(C) Entering the carbohydrate amount of the meal the PwD intends to eat. Alternatively, a meal may be selected from a food database of the diabetes manager. Based on the blood glucose value and the carbohydrate amount, the diabetes manager calculates an appropriate insulin bolus amount for the current time of day. For this purpose, a number of algorithms are known in the art, such as disclosed in the WO 2006/066926.
(D) The calculated bolus amount is displayed on the display of the diabetes manager and is confirmed by the PwD. Optionally, a further step may be carried out in which an appropriate administration profile over time is selected from a list for taking into account the carbohydrate absorption characteristics of different meals.
After a final confirmation by the PwD, the bolus amount is transmitted to the insulin pump which subsequently administers the bolus.
Depending on the specific system, the details and the sequence of the may vary. The above example is provided to illustrate a general procedure for programming a bolus without limiting the embodiments described herein.
As should now be apparent, programming a bolus may be difficult to perform discretely in a number of situations. For example, in a public restaurant or the like, the PwD may not be able to pierce the skin and place a drop of blood on a test strip without drawing undesired interest from others. Furthermore, in some cases, carrying the diabetes manager is inconvenient during mealtime and directly operating the insulin pump is indiscreet and/or uncomfortable when carried concealed from view.
Accordingly, a need exists for alternative ambulatory insulin infusion systems that can be conveniently and discretely operated.